It is well known that polymethylsilsesquioxane is a polymer comprising methylsilsesquioxane units which are trifunctional organosilicon units, and can take a fine powder form. The present inventors previously found a method for the preparation of a polymethylsilsesquioxane fine powder suitable as a material for electronic parts and an additive for polymers as disclosed in, for example, JP-A-63-77940 and 63-295637 (The term "JP-A" as used herein means an "unexamined published Japanese patent application").
Such a silicone resin fine powder comprising methylsilsesquioxane units is composed of minute spherical particules usually having a particle diameter of 0.05 to 100 .mu.m, and has advantages over silica in having a smaller specific gravity and better slip properties and being excellent in dispersibility into organic resins and organic liquids. However, there has not yet been obtained a silicone resin fine powder in which a hydrocarbon group substituted with a quaternary ammonium group is bonded to a silicone atom.
Since polymethylsilsesquioxane does not have a polar group in its molecule, it is not suitable for applications for which reactivity and appropriate hydrophilicity are required. Further, introduction of a physiologically active group into the polymer has not yet been successful.
On the other hand, a technique for obtaining spherical silica is known, which comprises subjecting a tetraalkoxysilane to hydrolytic polycondensation in alcohol containing aqueous ammonia, and JP-A-62-72514 discloses a method for introducing an organofunctional group by replacing part of the tetraalkoxysilane with an organotrialkoxysilane. However, this prior art reference fails to disclose introduction of an organofunctional group containing a quaternary ammonium group, this introduction being a characteristic feature of this invention, and further there is no description therein teaching or suggesting the application of such a fine powder to a coating composition etc., with the fine powder dispersed in an organic resin or organic liquid.